1. Field of the Invention
The present invention is related to a sensor device and an image forming apparatus, and more particularly to the sensor device having an optical detection system, and the image forming apparatus including the sensor device.
2. Description of the Related Art
An image forming apparatus such as a digital copier, a laser printer, or the like transfers a toner image onto a surface of a recording medium represented by a printing paper, and fixes an image by heating and pressing with a predetermined condition, to form the image. An image forming condition is considered such as a phenomenon condition, a transfer condition, a fixing condition, and the like for an image formation. Especially, in order to perform a higher quality image formation, it is required to set the image formation conditions individually depending on a recording medium.
This is because the image quality in the recording medium is greatly influenced by a quality of material, thickness, humidity, smoothness, coating states, and the like. For example, regarding the smoothness, a fixation rate of toner becomes lower for concave portions in an irregularity of the printing paper surface depending on a fixing condition. Therefore, in a case in which fixing is not performed with a proper condition corresponding to the recording medium, uneven coloring occurs.
Moreover, with progress of recent imaging devices and diversification of expression methods, there are more than several hundred types of the recording media only for printing paper. Furthermore, there is a wide variety of brands with differences in specifications such as basis weight or the thickness in each type. For the high quality image formation, it is necessary to set a detailed imaging condition depending on each one of these brands.
Also, recently, brands have increased regarding a plain paper; a coated paper represented by a gloss coated paper, a matte coated paper, and an art coated paper; a plastic sheet; and a special paper where an embossing process is performed on a surface.
In a current image forming apparatus, in a case of filling trays with paper, a user needs to set the brand of a paper and a print condition for each of the trays. Thus, there is an inconvenience for setting. The user is required to have knowledge for distinguishing the type of the paper. If a wrong setting is performed, the most suitable image is not acquired. Also, in a case in which the brand of the paper to use is unknown, it is difficult to determine which brand is to be set for the paper.
An optical method is known to emit light on a recording medium, to receive reflected light and transmission light, and to detect the brand and a surface state of the recording medium.
For example, Patent Document 1 discloses a recording material differentiation apparatus for determining the type of a recording material by using the reflected light and the transmission light.
Also, Patent Document 2 discloses a sheet material quality differentiating apparatus for differentiating material quality of a sheet material based on an amount of reflected light which is reflected at a surface of the sheet material and an amount of transmission light which is transmitted to the sheet material.
Also, Patent Document 3 discloses an image forming apparatus which includes a reflection type optical sensor for identifying the type of the recording material being accommodated in a paper feeding, an identification part for identifying presence or absence of the recording material being accommodated in the paper feeding and presence or absence of the paper feeding based on a detection output from the reflection type optical sensor.
Also, Patent Document 4 discloses an image forming apparatus which includes a state detection part for detecting multiple polarization elements of the reflected light by irradiating light to the recording medium, a high pressure supply part for supplying a high pressure output value to perform the image formation, and an output controller for controlling the high pressure output value of the high pressure supply part based on a detection result of the multiple polarization elements by the state detection part.
Also, Patent Document 5 discloses an optical sensor which includes an irradiation system for irradiating linear polarization light in a first polarization direction to a sheet-like object, a first light detection system which is arranged on a light path of light which is irradiated from the irradiation system and is reflected through specular reflection at an object, an optical element through which the linear polarization component is transmitted in a second polarization direction perpendicular to the first polarization direction of the light which is reflected through diffusion reflection at the object, and a second light detection part for receiving light transmitting through the optical element.
Also, Patent Document 6 discloses a printing apparatus which includes an information acquisition part for acquiring two sets of information corresponding to both front side and back side of a print medium being an object to print, and a determination part for determining a type of a print medium based on the two sets of information acquired by the information acquisition part, in which the information part acquires information of an image pattern which is obtained by imaging a configuration state of fiber of a surface of the print medium.
Also, Patent Document 7 discloses an apparatus for identifying a type of a recording medium, which includes a detection part having a set of a light emission part and a light reception part, and a recording medium conveying part, in which while fixing a location of the detection part, types of a first surface of the recording medium and a second surface being an opposite side of the first surface are identified by moving the recording medium by the recording medium conveying part.
However, it is difficult for the above described technologies to determine the type of the object at higher precision with a simple configuration.